Internal-combustion engine



July 30, 1929. 1 M. wooLsoN INTERNAL COMBUSTION ENGINE Filed Dec. 20,1925 777. Waals 011/ Patented July 30, 1929.

UNITED STATES PATENT oFFlcE.

LIONEL M. WOOLSON, OF DETROIT, MICHIGAN, ASSIGNOR T.0 PACKARD MOTOR CARCOMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN. I

INTERNAL-COMBUSTION IElNfirIhl'IEl.

Application led December 20, 1923. Serial No. 681,723.

This invention relates to internal combustion engines and particularlyto mixture controlling means therefor'.

A great variety of devices have heretofore been proposed forthermostatically controlling the mixture of an internal combustionengine. Where thermostats are arranged in the mixture line itself theaction is usually too slow in winter due to the very cold a'ir beingdrawn through the carburetor. Vhere the thermostat is arranged intheexhaust pipe the action is usually too sudden and there is the addedcomplication of a packed operating connection extending through theexhaust pipe, the heat of which rapidly deteriorates the packing; wherethe thermostat is mounted adjacent the exhaust pipe but onvthe outsidethereof the action is frequently too slow in cold weather because of thedraught of cold air passing over the engine from the fan which isusually arranged at the front of the engine when used in a motorvehicle; when the thermostat is used in the water circulation system itsaction is usually sluggish; and

there are numerous objections to the various other types of thermostatsused.

One of the objects of the present invention is to provide a mixturecontrol means which will act positively upon the mixture device 3o andwhich will not be too greatly aected by the outside temperatureconditions. Also, a

device is sought which will be rather stable d' in its action or whichwill not fluctuate too much With changes in operati-ng conditions.y

i Another object of the invention is to provide means acted upon by theengine exhaust for controlling in' a positive and accurate manner thecarburetor or mixture forming device of the engine.

Other objects of the invention will appear from the followingdescriptions taken in connection with the drawings, which form a part ofthis specification, and in which:

Fig. 1 is a perspective view of an internal combustion engine embodyingthe invention;

Fig. 2 is a side elevation of parts of the engine shown in Fig. 1,together with a somewhat diagrammatic showing of the movable or controlparts of the device, and

Fig. 3 is a sectional view of part of the engine carburetor takenthrough the mixture valve.

Referring to the drawing7 10 represents an lports of the engine.

engine cylinder block which is shown with a detachablehead 11 of usualform. A carbu* retor or mixture device 12 is mounted upon the side ofthe engine and is suitably connected by a pipe 13' with a passage in thecylinder block which carries the mixture to the inlet The carburetor hasa mlxture valve 14 which is yieldingly held closed'by one or moresprings 15, the tension of whlcli springs may be varied by a cam 16mounted upon a rock shaft 17 supported on the carburetor body. Themainintake 18 of the carburetor is controlled by a butterfly valve 19 heldyieldingly open by a spring 19 and which may be closed by the rockshaft17 near the end of its closing stroke, through a link 20, an arm 20 onthe shaft of the valve 19 and an arm 21 on the rock shaft 17. In Fig. 2the cam 16 and valve 19 are shown in full lines in their rich-mixtureposition and in dotted linesin their lean-mixture position.

Mounted u'pon the side of the cylinder block .10 is the engine exhaustpipe 22. This pipe 1s bolted to the cylinder block by several bolts suchas those shown at 23 and it will be noted that these bolts pass throughopenings 24 which 'are slightly larger than the bolt to thereby allowfor expansion lengthwise of the exhaust pipe. The exhaust pipe isusually made of cast iron and it Will, of course, expand as it is heatedup by the hot exhaust gas passing into it from the cylinders when theengine is in operation. As the exhaust pipe cools it again contracts toits normal length.

In the form of the invention shown the carr buretor 12 is mountedadjacent the exhaust pipe 22 so that the connecting mechanism forvarying the adjustment of the carburetor,

which is about to be described, may be of very simple form. Theinvention contemplates utilizing the expansion and contraction of' theexhaust pipe for-varying the richness of the mixturesupplied by thecarburetor. This is done by suitable connections from the exhaust pipeto the rock shaft 17 above referred A bar or rod 25 of Invar steel issupported lengthwise of the exhaust pipe 22, being attached near theleft-hand end of the exhaust pipe as shown at 26. The properties ofInvar steel are well known, this steel substantially retaining itsoriginal size regardless of 5 nected as at 27 to the short arm 28 of abell crank lever 29, the short arm extending downwardly from the pivot30 of the lever and the long'arm 31 extending substantially parallelwith the exhaust pipe. The adjusting means is shown at 32.

This lever 29 is mounted near the end of the exhaust pipe which isopposite the connection 26 and as the exhaust pipe expands with the heatandthe rod 25 retains its normal length,

the pivot 30 and'cons'equently the lever 29are moved towards the rightin Fig. 2, thus rocking the lever on its pivot and moving the arm 31upwardly to the dotted line position shown in said Fig. 2.

Mounted upon the exhaust pipe on a pivot 33, near the free end of thearm 31, is another bell crank lever 34 having a short horizontal arm 35and a` long downwardly, extending arm 36. An adjustable bolt 37 formsthe bearing point of the free end of the arm 31 on the arm 35 thusdetermining the relative position of those arms.

The arm 36 is connected by a link 38 with an arm 39 on the rock shaft 17above referred to so that the shaft 17 is rocked as the bell crank lever34 is moved on its pivot.

By reason of the tension of the springs 15 which rest against the cam16, there is a constant tendency, of course, for the shaft 17 to 35 berocked towards the dotted line position shown in Fig. 2. This will causethe arm 35 to be kept in contact with the arm 31 as the latter movesupwardly.

In operation, with Vthe engine cold, the parts 4o will be in theposition shownin full lines in '"Fg. 2; This is the rich-mixtureposition of the carburetor. The spring 15 is holding the valve 14 inclosed position and is also holding the bell crank lever 34 so that itsarm 35 is in contact with the point 37 of the arm 31. The

valve 19 is also in nearl closed position so that very little air is alowed to enter the carburetor 12. As the engine is cranked over by theelectric starter or otherwise, a

' 50 rich mixture is'fed to it and consequently it starts easily. As theexplosions occur in the cylinders and the latter exhaust into the pipe22, the exhaust pipe is heated and soon begins to expand lengthwise.This expansion of the exhaust pipe together with the non-exp ansion ofthe rod 25 causes the bell crank lever 29 to be rocked on its pivot 30so that the arm 31 moves upwardly. This permits the arm 35 to moveupwardly also and the arm 36 to move to the left in Fig. 2, the spring15 acting against the cam 16 to draw the arm 36 in that direction. Inthis Way the tension on the spring 15 becomes less and the valve 19 isfirst opened and then there is very little tension on the valve '14 sothat the latter will open ver y readily with the suction through thecarburetor and thussuicient air is admittedthrough the carburetor toprovide a lean running mixture. The exhaust pipe 22 soon reaches itsmaximum elongation and as long as the engine is running it maintains itselongated form relay tive to the rod 25. This position of the parts isshown in dot-ted lines in Fig. 2 and the exact desired mixture at thatpoint in the runy ning of the engine may be obtained by manipulating`the adjustments 32 and 37.

When the engine is stopped the exhaust pipe 22 cools very readilybecause of the large exposed surface and the 4parts resume the full lineposition shown in Fig. 2. In doing so the arm 31 moves downwardlyagainst the arm 35 thereby rocking the lever 34 and mov- Ving the arm 36towards the right. This rocks and may specifically claim, I do notdesire it to be understood that my invention is limited to the exactdetails of the construction, as it will be apparent that changes may bemade therein without departing from the spirit or scope of my invention.

Havingthus described my invention, what v I claim and desire to secureby Letters' Patent is:

1. In an internal combustion engine, the combination with the carburetorand the exhaust pipe thereof, of a rod of Invar steel Aconnected at oneend to one end of the exhaust pipe, a bell crank lever pivoted. adjacentthe other end of said exhaust pipe and having one of its arms connectedto the free end of said rod, a second lever. pivoted on said exhaustpipe, the other arm of the first -lever connected'to operate one of thearms of the second lever, and a connection from the second lever toJsaid 'carburetor'.

2. In an internal combustion engine, the combination of the exhaustpipe, a rod con-v nected at one end to one end of the exhaust pipe, abell crank lever having one short arm and one long arm and pivotallysupported on said exhaust pipe adjacent its other end, the short arm ofsaid lever being connected to said rod, a second lever pivotallysupported upon said exhaust pipe and having one short arm and one'longarm, the long arm of the first lever being adapted to contact with andoperate upon the short arm'of the second lever, and a mixturecontrolling device connected to the long arm of the second lever.

3. In an internal combustion engine, the combination of a cylinderblock, an exhaust pipe mounted thereon and adapted to receive theexhaust from the engine, a carburetor having an air valve and adapted toform a combustible fuel mixture for the engine, and

substantially non-expansible means actuated by the elongation of theexhaust pipe for controlling said valve to regulate the quality of saidfuel mixture.

4. In an internal combustion engine, the combination of a cylinderblock, an exhaust pipe mounted thereon, a carburetor having an airvalve, and substantially non-expansible means actuated by the elongationof the exhaust pipe for controlling said valve to Vary the richness ofthe carburetor mixture in accordance with the temperature of the engine.

5. In an internal combustion engine7 the combination of an expansibleexhaust pipe, a substantially non-expansible rod secured at one end tosaid exhaust pipe, a carburetor having an air Valve, and meansconnecting the other end of said rod to operate said Valve to increasethe proportion of air in the fuel mixture from the carburetor as theengine warms up.

6. In an internal combustion engine, the combination With the mixtureforming means thereof including an air valve, of an expansible exhaustpipe, a non-expansible rod, and connecting linkage between the exhastpipe, the rod and said air Valve adapted to regulate the mixture inaccordance with engine temperature.

In testimony whereof I afix my signature.

' LIONEL M. VVOOLSON.

